title: Measurement of activated coagulation time in children: evaluation of the blood-saving kaolin i-STAT activated coagulation time technique in pediatric cardiac anesthesia.
abstract: OBJECTIVE
  To compare the activated coagulation times (ACTs) measured with the blood-saving kaolin i-STAT 1 ACT technique (Abbott Point of Care Inc, Princeton, NJ) with ACTs obtained from the widely used ACTR II device (Medtronic, Inc, Minneapolis, MN) in children undergoing cardiac surgery.
  
  
  METHODS
  A prospective, observational single-center study.
  
  
  METHODS
  Forty-four pediatric cardiac surgery patients.
  
  
  METHODS
  Surgery was performed with cardiopulmonary bypass (CPB) necessitating heparinization.
  
  
  RESULTS
  ACTs measured on the i-STAT 1 device (2 × 95 μL) were compared with those obtained from the Medtronic ACTR II device (2 × 0.5 mL). Blood samples were drawn before, during, and after heparinization for CPB and paired for statistical analysis. The 2 techniques were compared using simple and multiregression analyses and the Bland-Altman method. In total, 179 intrarater and 142 interrater data pairs were analyzed. The intrarater reliability of the 2 devices was good, with a mean bias and limits of agreement of +2.0 and -55.5/+59.5 seconds for the Medtronic ACTR II and +0.5 and -59.9/+60.9 seconds for the i-STAT 1. An interrater reliability analysis of the mean of simultaneously measured ACT of the Medtronic ACTR II and both i-STAT 1 devices yielded a mean bias of -5.3 seconds and limits of agreement of -210.1/+199.5 seconds. A comparison of the higher of the paired ACT values from both devices showed similar results. After the removal of heparin, the i-STAT 1's ACT values became significantly lower than those measured on the Medtronic ACTR II (p < 0.001). Simple and multiregression analyses revealed that base excess independently influenced the mean bias of the ACT values from the Medtronic ACTR II (p = 0.037) and i-STAT 1 devices (p = 0.036).
  
  
  CONCLUSIONS
  The kaolin i-STAT 1 ACT technique agreed well with the Medtronic ACTR II technique during the nonheparinized phase that preceded CPB. The overall agreement between the ACT obtained from the 2 devices was poor. The routine use of i-STAT 1 measured ACT values cannot be recommended as a reliable alternative to the Medtronic ACTR II.
authors.affiliation: Section of Critical Care Medicine, Department of Pediatrics, Yale University, Yale New Haven Hospital, New Haven, CT 06520-8064, USA. francis.ulmer@yale.edu
authors.forename: Francis F
authors.initials: FF
authors.lastname: Ulmer
authors.forename: Werner
authors.initials: W
authors.lastname: Baulig
authors.forename: Dominique
authors.initials: D
authors.lastname: Béttex
authors.forename: Nelly
authors.initials: N
authors.lastname: Spielmann
authors.forename: Christoph
authors.initials: C
authors.lastname: Bürki
authors.forename: Markus
authors.initials: M
authors.lastname: Weiss
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000758:Anesthesia / Q000379:methods / Q000592:standards*; D001777:Blood Coagulation; D006348:Cardiac Surgical Procedures / Q000592:standards; D002315:Cardiopulmonary Bypass / Q000592:standards*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D010314:Partial Thromboplastin Time / Q000295:instrumentation / Q000379:methods / Q000592:standards; D011446:Prospective Studies; D014914:Whole Blood Coagulation Time / Q000295:instrumentation / Q000379:methods / Q000592:standards*